The Ministry of Defense's top scientific adviser told the government not to diss the Lancet survey, saying that its methods were "close to best practice" and the study design was "robust". The government was asked to explain how they accepted the methodology but publicly rubbished the findings, and said:

"The methodology has been used in other conflict situations, notably the Democratic republic of Congo.

"However, the Lancet figures are much higher than statistics from other sources, which only goes to show how estimates can vary enormously according to the method of collection.

"There is considerable debate amongst the scientific community over the accuracy of the figures."

That's some heavily fortified bullshit. On the one hand, of course different collection methods cause various results: that is one of the points addressed and repeatedly made in the survey by Roberts et al. On the other hand, the idea of "considerable debate" over the accuracy of the findings is almost entirely contrived. A number of interested parties have done so, referring to something called 'Main Street Bias'. The BBC reports:

Some scientists have subsequently challenged the validity of the Lancet study. Questions have been asked about the survey techniques and the possibility of "mainstreet bias".

Dr Michael Spagat of Royal Holloway London University says that most of those questioned lived on main streets which are more likely to suffer from car bombs: "It would appear they were only able to sample a small sliver of the country," he said.

Dr Spagat has previously conducted research with Iraq Body Count, an NGO that counts deaths on the basis of media reports and which has produced estimates far lower than those published in the Lancet.